Read Annie Dillard's short essay, "The Snake" from The Gulf Coast Reader. Then go OUT, with a pair of binoculars if possible). Go to a spot familiar or unfamiliar ... it doesn't matter (AS LONG AS YOU'RE OUTSIDE).
For the first five minutes, notice the big picture. Take notes on what you see. Then, look closely at one area or one object (ideally, using the binoculars). Watch for another five minutes, and then make notes on what you see in the "small" picture. When you get back inside, write up your notes in full sentences, adding in details as you go along.
NOTE: Where ever you go, don't take your laptop. Make notes by hand. Also, make sure you take in every sense and include it in your write-up (smell, taste, touch, sight, sound).